The invention relates to a compensator for a lack of parallelism in a removable vehicle seat.
It relates to motor vehicle seats and, more particularly, to removable seats comprising, on the one hand, means of anchorage to longitudinal slideways fixed to the floor of the vehicle and, on the other hand, means allowing their longitudinal position to be adjusted and allowing them to be locked in the chosen position.
In these seats, the sitting structure is secured to an underframe formed of two subassemblies, namely a right and a left subassembly, each comprising means of positioning with respect to the corresponding slideway, means of guidance in transverse and longitudinal translation with respect to the slideway, means of locking on the slideway, such as articulated bolts or catches collaborating with complementary means on the slideway, such as returns, teeth or notches.
In spite of the care taken when manufacturing and fitting the slideways, and also the underframes of each seat, the build-up of manufacturing tolerances may, for certain seat/slideway combinations, lead to jamming during, or portions offering greater resistance to, the longitudinal displacement of a seat underframe in the slideways.
In addition, over time, deformation to the floor may adversely affect the relative positions of two initially parallel slideways, giving them the shape of a xe2x80x9cVxe2x80x9d in plan view from above, and/or a different inclination with respect to the plane of the floor, that is to say may generate new conditions adversely affecting the sliding, and possibly even the return to its position when positioning the seat.
These disadvantages are encountered all the more when a passenger seat can occupy any position on the floor, because then the defects of the slideways combine with the defects of the seats.
Considering that the subassemblies, namely the right and left subassemblies, of the sitting structure, are connected rigidly to one another by crossmembers, the applicant company, in its French Patent Application published under the number 2 812 251 proposes to remedy these parallelism defects by equipping one of the endplates with at least one carriage which, on the one hand, is mounted so that it floats in terms of transverse translation with respect to this endplate and, on the other hand, is connected to the latter by a single transverse axle with the possibility of pivoting in the vertical plane.
The present invention aims to remedy these parallelism defects using a simpler less expensive compensator that can be applied to all seats in which the sitting structure of the seat comprises two rigid lateral endplates connected by crossmembers.
According to the invention, each of the crossmembers connecting the endplates of the seat is equipped, at least at one of its ends, with a cylindrical and stepped axial endpiece via which it is engaged with radial clearance in a sleeve made of viscoelastic material itself pushed tightly into a bearing in the corresponding endplate, said endpiece being equipped with an axial tapped hole for a screw for translational immobilization pressing a washer against the outer end face of the sleeve and the other end face of the sleeve against the flange of said endpiece.
Thus, when there is a parallelism defect in the connection between a seat and its two slideways, whether this be during engagement of the seat in its slideways or as the seat is displaced therein, the reaction forces imparted to the two endplates are compensated for, and at least partially absorbed, by the deformation of the viscoelastic sleeves. This deformation, which does not affect the connection between the two endplates, allows these to modify their relative position and eliminate any jamming of their carriage or running in the slideways.